Mitamura Katsuya, Norikane Takashi, Yamamoto Yuka, Fujimoto Kengo, Takami Yasukage, Hoshikawa Hiroshi, Toyohara Jun, Nishiyama Yoshihiro
Department of Radiology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan.
Department of Otolaryngology, Faculty of Medicine, Kagawa University, Kagawa, Japan.
EJNMMI Res. 2021 Feb 10;11(1):13. doi: 10.1186/s13550-021-00749-y.
We investigated the potential of interim 4'-[methyl-C]thiothymidine ([C]4DST) PET for predicting the chemoradiotherapeutic response for head and neck squamous cell carcinoma (HNSCC), in comparison with 2-deoxy-2-[F]fluoro-D-glucose ([F]FDG) PET.
A total of 32 patients with HNSCC who underwent both [C]4DST and [F]FDG PET/CT before therapy (baseline) and at approximately 40 Gy point during chemoradiotherapy (interim) were available for a retrospective analysis of prospectively collected data. The baseline was treatment-naïve PET/CT scan as part of staging. The maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV) from [F]FDG PET or proliferative tumor volume (PTV) from [C]4DST PET, and total lesion glycolysis (TLG) from [F]FDG PET or total lesion proliferation (TLP) from [C]4DST PET were measured. MTV or PTV was defined as the volume with an SUVmax greater than 2.5. The differences in SUVmax (ΔSUVmax), MTV (ΔMTV) or PTV (ΔPTV) and TLG (ΔTLG) or TLP (ΔTLP) from baseline to interim PET scans were calculated. Patients without or with evidence of residual or recurrent disease at 3 months after completion of chemoradiotherapy were classified as showing a complete response (CR) and non-CR, respectively.
All patients showed increased uptake in primary tumor on baseline [C]4DST and [F]FDG PET studies. All patients showed increased uptake on interim [F]FDG PET, whereas 18 patients showed no increased uptake on interim [C]4DST PET. After chemoradiotherapy, 25 patients were found to be in CR group and 7 to be in non-CR group. [C]4DST ΔSUVmax, ΔPTV, and ΔTLP for CR group showed significantly greater reductions than the corresponding values for non-CR group (P = 0.044, < 0.001, < 0.001, respectively). However, there were no significant differences in [F]FDG ΔSUVmax, ΔMTV, or ΔTLG between CR group and non-CR group. [C]4DST ΔMTV of -90 was the best cutoff value for the early identification of patients with non-CR.
These preliminary results suggest that interim [C]4DST PET might be useful for predicting the chemoradiotherapeutic response in patients with HNSCC, in comparison with [F]FDG PET.
我们研究了中期4'-[甲基 - C]硫代胸腺嘧啶核苷（[C]4DST）PET与2-脱氧-2-[F]氟 - D - 葡萄糖（[F]FDG）PET相比，预测头颈部鳞状细胞癌（HNSCC）放化疗反应的潜力。
共有32例HNSCC患者在治疗前（基线）以及放化疗期间约40 Gy时接受了[C]4DST和[F]FDG PET/CT检查，可用于对前瞻性收集的数据进行回顾性分析。基线检查为作为分期一部分的初治PET/CT扫描。测量了[F]FDG PET的最大标准化摄取值（SUVmax）、代谢肿瘤体积（MTV）或[C]4DST PET的增殖肿瘤体积（PTV），以及[F]FDG PET的总病变糖酵解（TLG）或[C]4DST PET的总病变增殖（TLP）。MTV或PTV定义为SUVmax大于2.5的体积。计算从基线到中期PET扫描的SUVmax（ΔSUVmax）、MTV（ΔMTV）或PTV（ΔPTV）以及TLG（ΔTLG）或TLP（ΔTLP）的差异。放化疗完成后3个月无残留或复发疾病证据或有残留或复发疾病证据的患者分别分类为显示完全缓解（CR）和非CR。
所有患者在基线[C]4DST和[F]FDG PET研究中均显示原发肿瘤摄取增加。所有患者在中期[F]FDG PET上摄取增加，而18例患者在中期[C]4DST PET上摄取未增加。放化疗后，发现25例患者在CR组，7例在非CR组。CR组的[C]4DST ΔSUVmax、ΔPTV和ΔTLP显示出比非CR组相应值显著更大的降低（分别为P = 0.044、<0.001、<0.001）。然而，CR组和非CR组之间的[F]FDG ΔSUVmax、ΔMTV或ΔTLG没有显著差异。[C]4DST ΔMTV为-90是早期识别非CR患者的最佳临界值。
这些初步结果表明，与[F]FDG PET相比，中期[C]4DST PET可能有助于预测HNSCC患者的放化疗反应。
